39) Let us count the probability of the “positive” test:P(T)=P(D)×P(T/D)+P(H)×P(T/H)==(1/10000)×0.99+(9999/10000)×0.01=0.010098≈0.01Now, we apply Bayes’ theorem:P(D/T)= P(D)×P(T/D)/P(T)=(1/10000)×0.99/0.01≈0.01